To date, it has been very difficult to mold any product having an undercut opening. The difficulties occur because the mold parts or opens in a direction at right angles to the material in the product covering the undercut opening. Therefore, in a standard mold arrangement the mold part around which the undercut opening would be formed, would catch on the material covering the undercoat opening and prevent the mold from opening.
The present invention relates to a method of molding a product having a first opening bordered by a wall around the first opening and a second opening through the wall at generally right angles to the first opening. The second opening is undercut beneath a ledge of rigid material formed on the product. The product is formed in a mold having first and second mold sections which open and close at a first parting line and the first mold section in itself comprises first and second mold parts which open and close at a second parting line. The method comprises closing the first and second mold sections to define a mold cavity, portions of which run along each of the first and second parting lines to define a mold cavity at the first and second parting lines. The mold cavity defined at the second parting line extends between only one of the mold parts and the second mold section. The method further consists of flowing mold material into the mold cavity, setting the mold material in the mold and thereafter opening the first and second mold sections and opening the first and second mold parts in a direction consistent with the direction of opening of the first and second mold sections and finally releasing the product from between the first and second mold parts.